This invention relates to a pump. More particularly the present invention relates to a membrane pump.
Pumps, which incorporate a flexible element to achieve the pumping action, are known. For example, the flexible element can be in the form of a deformable tube or membrane. A deformable tube pump is described in our international patent specifications WO 99/01687 and WO 02/18790.
A membrane pump is disclosed in our PCT specification, WO 2005/088128. That pump uses an elastomeric membrane which is clamped between two pump halves. The membrane has outer dimensions greater than the size of the recess in which it is located, such that compressive forces are created in the elastomeric membrane. This pump provides an improved membrane life over prior pumps. However, the Applicant has found that still further improvements are possible in membrane pumps in order to improve the membrane life, accuracy and other operating parameters of the pump.